This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-193209, filed June 27, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to improvement of an information recording and reproducing apparatus and an information recording and reproducing method for recording and reproducing digital information, say, on an optical disk. Further, the present invention relates to improvement of an information reproducing apparatus and an information reproduction method for reproducing digital information recorded on, say, an optical disk. Moreover, the present invention relates to an information recording medium such as an optical disk for recording, say, digital information.
It is well known that a DVD system is spreading. The DVD system reproduces digital information (movies, voice, and the like) equivalent to the reproduction time of 2 hours or more. The digital information is compressed and recorded on one side of a 12 cm diameter optical disk by using the MPEG (Moving Picture Image Coding Experts Group)-2 encoding.
The current DVD system standard specifies a recording capacity of 4.7 GB (gigabytes) on one side of an optical disk, a track density of 0.74 xcexcm per track, and a linear density of 0.267 xcexcm per bit. In the following description, a DVD system based on this DVD standard is referred to as the current DVD system.
When reading an analog reproduction signal from an optical disk, the current DVD system uses an equalizer to amplify high-frequency components for correctly and accurately converting this signal to digital information and decreasing error occurrences.
Conventionally, the equalizer characteristic is fixed. Recently, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 9-82025 and the like, there is provided a feature called the adaptive equalization. It automatically controls to optimize the equalizer characteristic according to an optical disk characteristic.
However, the adaptive equalization means disclosed in this KOKAI Publication reads the number of Cl errors according to error correcting codes and controls the equalizer""s tap coefficient by means of the hill-climbing control. Since a specified period is needed for monitoring an error occurrence situation, it is difficult to realtime control the equalizer characteristic.
Conventionally, the waveform slice method has been widely used for realtime controlling the equalizer characteristic. Currently, the PRML (Partial Response and Maximum Likelihood) method is increasingly used as a solution for decreased SNR (Signal to Noise Ratio) of the reproduction signal.
The reproduction signal processing method such as PRML performs waveform equalization based on an amplitude level of the reproduction signal. According to a technique developed for this reproduction signal processing method, known training data is recorded on a recording medium. When reproducing the training data causes an equalization error, this error is used for recording medium evaluation or circuit adjustment reference.
A system using the training data for evaluating recording media or adjusting circuits is just in a developmental stage. For example, there is the problem that relation between a training data pattern and ordinary data may prevent full circuit adjustment or accurate recording medium evaluation.
The present invention has been made in consideration of the foregoing. It is therefore an object of the present invention to provide information recording and reproducing apparatus and information recording and reproducing method, information reproducing apparatus and information reproducing method, and information recording medium capable of solving the problems due to conventional training data and performing full circuit adjustment and accurate recording medium evaluation.
An information recording and reproducing apparatus according to the present invention comprises:
recording section having first selection section for selecting user data and training data based on a recording address, modulation section for creating a plurality of modulation data candidates with respect to data selected by this first selection section, second selection section for selecting various modulation data candidates created by this modulation section, a counter for counting DSVs in modulation data selected by this second selection section, and control section for setting a DSV output from this counter to a specified value with the training data selected by the first selection section, wherein the recording section records modulation data selected by the second selection section on an information recording medium; and
reproduction section having equalization section for equalizing a reproduction signal read from the information recording medium based on an equalization coefficient, discrimination section for discriminating output from this equalization section, training data generation section for outputting predetermined training data based on output from this discrimination section, polarity test means for testing a polarity of training data output from this training data generation section based on output discrimination data of the discrimination section, ideal signal generation section for generating an ideal signal when relevant training data is ideally equalized from output of this polarity test section, operation section for computing an equalization error based on output from this ideal signal generation section and output from the equalization section, and coefficient control section for generating an equalization coefficient supplied to the equalization section based on output from this operation section and a reproduction signal input to the equalization section.
An information recording and reproducing method according to the present invention comprises:
a recording step having a first step of selecting user data and training data based on a recording address, a second step of creating a plurality of modulation data candidates with respect to data selected by this first step, and a third step of counting DSVs in single modulation data selected from various modulation data candidates created at this second step to control selection of the various modulation data candidates and setting the counter for counting DSVs to a specified value with training data selected at the first step, wherein the recording step records modulation data selected at the third step on an information recording medium; and
a reproduction step having a fourth step of equalizing a reproduction signal read from the information recording medium based on an equalization coefficient, a fifth step of discriminating an equalization signal obtained at this fourth step, a sixth step of outputting predetermined training data based on discrimination data obtained at this fifth step, a seventh step of testing a polarity of training data output from this sixth step based on output discrimination data obtained at the fifth step, an eighth step of generating an ideal signal when relevant training data is ideally equalized from training data obtained at the seventh step, a ninth step of computing an equalization error based on an ideal signal obtained at this eighth step and an equalization signal obtained at the fourth step, and a tenth step of generating an equalization coefficient supplied to the fourth step based on an equalization error obtained at this ninth step and a reproduction signal before processing at the fourth step.
An information reproducing apparatus according to the present invention reproduces digital data recorded on an information recording medium, comprising:
an equalization section for equalizing a reproduction signal read from the information recording medium based on an equalization coefficient, a discrimination section for discriminating output from this equalization section, an error correction section for correcting an error in output from this discrimination section, a modulation section for creating a plurality of modulation data candidates for output from this error correction section and, out of this plurality of modulation data candidates, outputting modulation data having practically a higher correlation with discrimination data obtained from the discrimination section, an ideal signal generation section for generating an ideal signal when modulation data output from this modulation section is ideally equalized, an operation section for computing an equalization error based on output from this ideal signal generation section and output from the equalization section, and a coefficient control section for generating an equalization coefficient supplied to the equalization section based on output from this operation section and a reproduction signal input to the equalization section.
An information reproducing method according to the present invention reproduces digital data recorded on an information recording medium, comprising:
an equalization step of equalizing a reproduction signal read from the information recording medium based on an equalization coefficient, a discrimination step of discriminating an equalization signal obtained at this equalization step, an error correction step of correcting an error in discrimination data obtained at this discrimination step, a modulation step of creating a plurality of modulation data candidates for data obtained at this error correction step and, out of this plurality of modulation data candidates, outputting modulation data having practically a higher correlation with discrimination data obtained at the discrimination step, an ideal signal generation step of generating an ideal signal when modulation data obtained at this modulation step is ideally equalized, an operation step of computing an equalization error based on an ideal signal obtained at this ideal signal generation step and an equalization signal obtained at the equalization step, and a coefficient control step of generating an equalization coefficient supplied to the equalization step based on an equalization error obtained at this operation step and a reproduction signal before equalization at the equalization step.
An information recording medium according to the present invention records training data on a plurality of discontinuous locations in the above-mentioned information recording and reproducing apparatus and the information recording and reproducing method.
According to the above-mentioned configuration and method, it is possible to solve the problems due to conventional training data and perform full circuit adjustment and accurate recording medium evaluation.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.